package com.example.chat.base.blur;

import android.graphics.Bitmap;

/**
 * Copyright (C) 2015 Wasabeef
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

public class FastBlur {

        public static Bitmap blur(Bitmap sentBitmap, int radius, boolean canReuseInBitmap) {

                // Stack Blur v1.0 from
                // http://www.quasimondo.com/StackBlurForCanvas/StackBlurDemo.html
                //
                // Java Author: Mario Klingemann <mario at quasimondo.com>
                // http://incubator.quasimondo.com
                // created Feburary 29, 2004
                // Android port : Yahel Bouaziz <yahel at kayenko.com>
                // http://www.kayenko.com
                // ported april 5th, 2012

                // This is a compromise between Gaussian Blur and Box blur
                // It creates much better looking blurs than Box Blur, but is
                // 7x faster than my Gaussian Blur implementation.
                //
                // I called it Stack Blur because this describes best how this
                // filter works internally: it creates a kind of moving stack
                // of colors whilst scanning through the image. Thereby it
                // just has to add one new block of color to the right side
                // of the stack and remove the leftmost color. The remaining
                // colors on the topmost layer of the stack are either added on
                // or reduced by one, depending on if they are on the right or
                // on the left side of the stack.
                //
                // If you are using this algorithm in your code please add
                // the following line:
                //
                // Stack Blur Algorithm by Mario Klingemann <mario@quasimondo.com>

                Bitmap bitmap;
                if (canReuseInBitmap) {
                        bitmap = sentBitmap;
                } else {
                        bitmap = sentBitmap.copy(sentBitmap.getConfig(), true);
                }

                if (radius < 1) {
                        return (null);
                }

                int w = bitmap.getWidth();
                int h = bitmap.getHeight();

                int[] pix = new int[w * h];
                bitmap.getPixels(pix, 0, w, 0, 0, w, h);

                int wm = w - 1;
                int hm = h - 1;
                int wh = w * h;
                int div = radius + radius + 1;

                int r[] = new int[wh];
                int g[] = new int[wh];
                int b[] = new int[wh];
                int rsum, gsum, bsum, x, y, i, p, yp, yi, yw;
                int vmin[] = new int[Math.max(w, h)];

                int divsum = (div + 1) >> 1;
                divsum *= divsum;
                int dv[] = new int[256 * divsum];
                for (i = 0; i < 256 * divsum; i++) {
                        dv[i] = (i / divsum);
                }

                yw = yi = 0;

                int[][] stack = new int[div][3];
                int stackpointer;
                int stackstart;
                int[] sir;
                int rbs;
                int r1 = radius + 1;
                int routsum, goutsum, boutsum;
                int rinsum, ginsum, binsum;

                for (y = 0; y < h; y++) {
                        rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
                        for (i = -radius; i <= radius; i++) {
                                p = pix[yi + Math.min(wm, Math.max(i, 0))];
                                sir = stack[i + radius];
                                sir[0] = (p & 0xff0000) >> 16;
                                sir[1] = (p & 0x00ff00) >> 8;
                                sir[2] = (p & 0x0000ff);
                                rbs = r1 - Math.abs(i);
                                rsum += sir[0] * rbs;
                                gsum += sir[1] * rbs;
                                bsum += sir[2] * rbs;
                                if (i > 0) {
                                        rinsum += sir[0];
                                        ginsum += sir[1];
                                        binsum += sir[2];
                                } else {
                                        routsum += sir[0];
                                        goutsum += sir[1];
                                        boutsum += sir[2];
                                }
                        }
                        stackpointer = radius;

                        for (x = 0; x < w; x++) {

                                r[yi] = dv[rsum];
                                g[yi] = dv[gsum];
                                b[yi] = dv[bsum];

                                rsum -= routsum;
                                gsum -= goutsum;
                                bsum -= boutsum;

                                stackstart = stackpointer - radius + div;
                                sir = stack[stackstart % div];

                                routsum -= sir[0];
                                goutsum -= sir[1];
                                boutsum -= sir[2];

                                if (y == 0) {
                                        vmin[x] = Math.min(x + radius + 1, wm);
                                }
                                p = pix[yw + vmin[x]];

                                sir[0] = (p & 0xff0000) >> 16;
                                sir[1] = (p & 0x00ff00) >> 8;
                                sir[2] = (p & 0x0000ff);

                                rinsum += sir[0];
                                ginsum += sir[1];
                                binsum += sir[2];

                                rsum += rinsum;
                                gsum += ginsum;
                                bsum += binsum;

                                stackpointer = (stackpointer + 1) % div;
                                sir = stack[(stackpointer) % div];

                                routsum += sir[0];
                                goutsum += sir[1];
                                boutsum += sir[2];

                                rinsum -= sir[0];
                                ginsum -= sir[1];
                                binsum -= sir[2];

                                yi++;
                        }
                        yw += w;
                }
                for (x = 0; x < w; x++) {
                        rinsum = ginsum = binsum = routsum = goutsum = boutsum = rsum = gsum = bsum = 0;
                        yp = -radius * w;
                        for (i = -radius; i <= radius; i++) {
                                yi = Math.max(0, yp) + x;

                                sir = stack[i + radius];

                                sir[0] = r[yi];
                                sir[1] = g[yi];
                                sir[2] = b[yi];

                                rbs = r1 - Math.abs(i);

                                rsum += r[yi] * rbs;
                                gsum += g[yi] * rbs;
                                bsum += b[yi] * rbs;

                                if (i > 0) {
                                        rinsum += sir[0];
                                        ginsum += sir[1];
                                        binsum += sir[2];
                                } else {
                                        routsum += sir[0];
                                        goutsum += sir[1];
                                        boutsum += sir[2];
                                }

                                if (i < hm) {
                                        yp += w;
                                }
                        }
                        yi = x;
                        stackpointer = radius;
                        for (y = 0; y < h; y++) {
                                // Preserve alpha channel: ( 0xff000000 & pix[yi] )
                                pix[yi] = (0xff000000 & pix[yi]) | (dv[rsum] << 16) | (dv[gsum] << 8) | dv[bsum];

                                rsum -= routsum;
                                gsum -= goutsum;
                                bsum -= boutsum;

                                stackstart = stackpointer - radius + div;
                                sir = stack[stackstart % div];

                                routsum -= sir[0];
                                goutsum -= sir[1];
                                boutsum -= sir[2];

                                if (x == 0) {
                                        vmin[y] = Math.min(y + r1, hm) * w;
                                }
                                p = x + vmin[y];

                                sir[0] = r[p];
                                sir[1] = g[p];
                                sir[2] = b[p];

                                rinsum += sir[0];
                                ginsum += sir[1];
                                binsum += sir[2];

                                rsum += rinsum;
                                gsum += ginsum;
                                bsum += binsum;

                                stackpointer = (stackpointer + 1) % div;
                                sir = stack[stackpointer];

                                routsum += sir[0];
                                goutsum += sir[1];
                                boutsum += sir[2];

                                rinsum -= sir[0];
                                ginsum -= sir[1];
                                binsum -= sir[2];

                                yi += w;
                        }
                }

                bitmap.setPixels(pix, 0, w, 0, 0, w, h);

                return (bitmap);
        }
}